Method of patching



June 20,1950 H. Poss METHOD OF PATCHING Filed Sept. 7, 1944 IN VEN TOR.

HARVEY POSS ATTORNEY Patented June 20, 1950 um'rso STATES PATENT? OFFICE METHOD OF PATCHING H v y P Stth ws, KX -a ass gnor to Curtiss-Wright Corporation, a corporation Application S pt m 7, 1944 4 Claims. 1

This invention is directed to a meth d. of hatching and repairing generally, and applies more specifically to a method for applying patches of a nature particularly adapted for r Pairing holes or minor damages in sheet material or surface coverings.

The invention is capable of use in the art of repairing and patching punctures, perforations, tears,.holes and the like in tanks, hulls of boats, pontoons, in the skin coverings. of airplanes, flying boats or fuselage and Wing surfaces and is particularly well suited for use in places ordinarily inaccessible from the inside.

A primary object is the method of patching comprising en ral y t ps of pr paring a hole or other aperture for receiving a repair patch, fitting the patch material in its intended position and reinforcing and permanently securing the patch in place so that the finally repaired surface is restored to its original strength and outward appearance.

A further object of this invention is to provide a method of blind patching, that is a method of patching a hole or puncture in askin surface where the entire operation is most conveniently performed from the outside or exposed surface,

Still another object is to devise a method or Placing. clamping and compressing a surface patch in position and. at the same time provide for the ready removal of certain of the clamping and compressing means without affecting the patching work or requiring that the patched zone of the work be accessible, from both sides.

The nature and scope of the invention will be better understood from the de a eddescr ption about tobe given in connection with the acc m- Danying drawings in which: t

F u .1 is a fragmentary perspective view of a, patched skin surface and in which. the pat has b en applied in acco dance .j'with the method hereof.

Figure .2 is another pers ective ie f ask n patch in process of appli a io Fi ure 31s an enla g dfs'ectiohai elevati n 01 stretch joint which is ing held unde comp Sion by the use of the clamping devices herein preferred, and

Figure 4 is a detail view of a clamping device with the several parts and" elements thereof shown when disassembled.

The present invention is illustrated in the accompan ing rawings an in. igure 1 of which there is shown a patch Ill which ha e co pletely s t in place in, a surroun inesh t ,cov ing or othersuriacematerialil and' whichis held permanentlyin p ace y a s able sin or other bonding material applied on the contacting surfaces of a scarf joint formed between the patch and the adjacent sheet m teriaI. One of. h i portant. features of the present. invention resides in the fact that a patchy of the nature herein contemplated is further strengthened by means f backing t ips. l2v permanently secured alone the joint area of th patch and held i place not only withglue or other bonding compound but bythe addition of a series of spaced dowel pins I 3, each or which is inserted in a suitable aperture with a head portion I4 brought into contact with the under surface of the backing strips. A study of Figure 1 will show the features of this invention as above noted.

In Figure 2 there is illustrated the several steps of a preferred method forcarrying out the patchingof boat hulls, aircraft fuselage skins and the like. It is contemplated herein that the patch be set in place from one side of the skin or sheet material It in the following manner. The mar-.- gin or lip portion of the damaged skin is first, tapered or beveled as at l5 and in like manner the matching lip portion of the patch Ill is tapered or beveled as at i6 so that the. patch will lie flush with he general exterior surface of he. sheet or skin H. Suitable backing strips [2 are then inserted through the open area to be patched and are positioned along the marginal under surface or he sh et H. Thes s rips ar held in this position by means of the dowel pins l3, ach of wh h i adapted o project consid r ably above the face plane of the sheet II. The pat h in. is then pe forated around its lip e it and p acedin. position by sliding the same o er the dowel p ns- With. this much of he patching proce s com 'lleted,v glu or any other suitable bonding a ent may then he applied to the. tapered or beveled jo nt formed between the pa ch i0 and heet II as well as on. th surfac of he backing s rips I: which lie adiaoe e un r su ce f the sheet I 1. Furthermore. t i same b nd ng ag nt or glue is applied to the portions of the dowel pin confined o buri d i t ac strips 2 n patch l0 and sheet ll respectively. Following the application of the glue, compression pads I! are then positioned over the dowel pins so that they overlie or are in registry with the backing strips before mentioned. If these pads tend to stick tothe patch it may be necessary to lay a sheet of cellophane or other material 18 over the patchsurta a A seri s of c amp d vi s i9, la to be described, are thendisposed ov r the dow l pins and by suitable manipulation of these clamps a compression load is exerted on the patch joint to render the gluing or bonding agent more effective as is well understood. The clamps l9 and the compression pads I! may be removed after the glue or bonding agent has completely set. Following the removal of these parts, the portions of the dowel pins which project above the surface of the patch may then be severed or otherwise cut off so that the end faces thereof lie flush with the surface of the patch or sheet material. The final form of the patch is clearly shown in Figure l.

Referring now in detail to Figures Band 4 there is illustrated a form of clamping device [9 which may be employed in carrying out the above described method of patching sheet material. In

Figure 4, for example, the clamp is shown as comprising a pad or foot plate member formed with an upstanding and centrally disposed tubular portion 2 l which has been threaded on its exterior surface. For cooperation with the threaded portion 2| of the foot plate there is provided a tubular torque element 22 having an interiorly threaded portion 23 which is adapted to be threaded on to the portion 2|. Suitable finger grip elements or wing rods 24 project laterally on opposite sides of the threaded or nut-like element 23 and are provided to facilitate the rotation of torque element 22. In addition a saddle plate 25 of a generally shallow channel section is provided to receive and support on the upper end of the torque element a clamp jaw device 26. The clamp jaw device includes a pair of jaw elements 21 each of which may be formed from sheet material or may be .cast to the shape desired. Each of these jaws 2'! is provided with a pair of forwardly projecting ears 28 by means of which laterally spaced and suitable pivotal connection may be formed by means of a pair of stub shafts 29 secured in position in the usual manner as by peening the end thereof to form a holding flange. In addition, each of the jaw elements 21'is provided with a suitably roughened or serrated working surface 3!] so that the outer or shank portion of the dowel pin which passes through the jaw throat (Figure 3) may be gripped and retained therein upon oppositely pivotally actuating" the jaw elements 21.

In Figure 3 the clamping device has been shown in detail. For example, the clamp foot plate 2!! assumes a position over the upstanding portion of the dowel pin H3. The thimble or torque element fiiis then threaded downwardly over the portion 2| to a suitable position as shown. The saddle plate 25 is positioned on top of the'thimble 22 and is retained in this position by the dowel pin l3 passing through a suitable aperture formed in its base surface, and the clamping member .26 is then positioned on the saddle in position to grip the dowel pin [3. With the clamp parts thus assembled, the lap joint [5-16 between the sheet material H and the patch I0 may be subjected to compression by outwardly threading thetorque element 22, the outward movement ofwhich acts to draw the dowel pin head portion 14 against the backing stn'p l2 and at the same time to move the foot plate 20 toward the compression pad I! thereby subjecting the interposed patch and sheet material to the desired compressive force.

Once the glue or bonding agent has set satis factorily the clamps may be removed together with the compression pads- I1. The upstanding portions of pins l3 are then cut ofi flush with the face surface of the patch so that the finished patch appears as shown in Figure 1.

The advantage of this method of patching lies in the fact that the patch joint is adequately and permanently reinforced by the presence of the underlying or backing strips. The dowel pins remaining in the patch also contribute to the strength of the patch joint and are considerably more advantageous than "the employment of nails or similar securing elements heretofore employed in patching and repairing. Other advantages will become evident from a study of the above detailed description.

The above described method for patching and repairing may be found especially useful in the repair of wood panels, ply-wood skin sections of aircraft, wood boat hulls and the like. With certain modifications the method may also be applied to the patching ofimetal sheets and coverings. Therefore, it should be understood that the scope of the present invention shall not be limited except to the extent required by the claims here appended.

What is claimed is:

1. In the method of setting an overlapping patch in place in a surface covering, the steps of permanently reinforcing with backing strips the opposite side of the overlapping area to be patched, further permanently strengthening the patch. by means of a series of spaced headed dowel pins, each dowel pin being passed outwardly through the backing strips and the overlapped patch and covering to cause the heads of the pins to contact said backing strips, temporarily reinforcing outer face of the patch by means which are guided into position over the outwardly projectingends of dowel pins, exerting inwardly directed compressive forces against the temporary reinforcing means with the outward reactions of said forces being exerted upon said outwardly projecting portions of the dowel pins to thereby compress the patch between the backing strips and said temporary reinforcing means to secure a firm bond between the patch and the covering upon the application of a bonding agent to the contacting surfaces therebetween, and finally removing said temporary reinforcing means and severing the dowel pins at the face of the patch, whereby the face area of the patch is left smooth while the backing strips are securely anchored in position by the dowel pin portions remaining in the patch.

2. In the method of setting a patch in placeas described in the preceding claim and in which the dowel pins arefgripped by clamping. means which are extended in a direction axially of the pins to apply said inwardly directed compressive forces against the temporary reinforcing means.

.3. A- methodof patching a perforated surface which comprises preparing the marginal edges of the perforation to receive a patch in overlapped relation, positioning backing strips along the opposite margins of the perforation, retaining the backing strips in position by a series of outwardly projecting dowel pins provided with means to engage the exposed surface of said backing strips, utilizing the projecting portions of .the dowel pins to guide a previously prepared patch into overlapping position over said marginal edges, exerting inwardly directed compressive forces along thepatch margins with the outward reactions of said forces being exerted upon the dowel pin projections, thereby to secure a;.per-,

, manent bond along the patch. margins after the applicationbf a bonding agent therebetween, and

thereafter severing the dowel pin projections flush with the patch to present a smooth patched surface which is reinforced by the presence of the backing strips and dowel pins.

4. A method of patching a perforated surface which comprises preparing the marginal edges of the perforation to receive a patch by scarfing the edge portions around the perforation, positioning backing strips to underlie said edge portions, retaining the backing strips in position by a series of outwardly projecting dowel pins having means to engage the under surfaces of said backing strips, utilizing the projecting portions of the dowel pins to guide a previously prepared marginally scarfed patch into recessed position over the perforation, exerting inwardly directed compressive forces along the patch margins with the outward reactions of said forces being exerted upon the dowel pin projections, thereby to secure the application of a bonding agent therebetween,

6 and, subsequently to setting up of said bonding agent, severing the dowel pin projections flush with the patch to present a smooth patched surface which is reinforced by the presence of the backing strips and dowel pins.

HARVEY POSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 863,650 Rockwell Aug. 20, 1907 1,552,954 Rockwell Sept. 8, 1925 1,938,816 Eger Dec. 12, 1933 2,094,779 Donaldson Oct. 5, 1937 2,102,558 Johnson Dec. 14, 1937 2,136,875 Blane Nov. 15, 1938 2,263,536 Dike Nov. 18, 1941 2,395,656 Chatfield Feb. 26, 1946 

